[14/16] KVM: VMX: Move NMI/exception handler to common helper

Commit Message

Binbin Wu Dec. 9, 2024, 1:07 a.m. UTC

From: Sean Christopherson <[e-mail]>

TDX handles NMI/exception exit mostly the same as VMX case.  The
difference is how to retrieve exit qualification.  To share the code with
TDX, move NMI/exception to a common header, common.h.

No functional change intended.

Signed-off-by: Sean Christopherson <[e-mail]>
Signed-off-by: Isaku Yamahata <[e-mail]>
Co-developed-by: Binbin Wu <[e-mail]>
Signed-off-by: Binbin Wu <[e-mail]>
---
TDX interrupts breakout:
 - Update change log with suggestions from (Binbin)
 - Move the NMI handling code to common header and add a helper
   __vmx_handle_nmi() for it. (Binbin)
---
 arch/x86/kvm/vmx/common.h | 72 ++++++++++++++++++++++++++++++++++++
 arch/x86/kvm/vmx/vmx.c    | 77 +++++----------------------------------
 2 files changed, 82 insertions(+), 67 deletions(-)

Patch

diff --git a/arch/x86/kvm/vmx/common.h b/arch/x86/kvm/vmx/common.h
index a46f15ddeda1..809ced4c6cd8 100644
--- a/arch/x86/kvm/vmx/common.h
+++ b/arch/x86/kvm/vmx/common.h
@@ -4,8 +4,70 @@ 
 
 #include <linux/kvm_host.h>
 
+#include <asm/traps.h>
+#include <asm/fred.h>
+
 #include "posted_intr.h"
 #include "mmu.h"
+#include "vmcs.h"
+#include "x86.h"
+
+extern unsigned long vmx_host_idt_base;
+void vmx_do_interrupt_irqoff(unsigned long entry);
+void vmx_do_nmi_irqoff(void);
+
+static inline void vmx_handle_nm_fault_irqoff(struct kvm_vcpu *vcpu)
+{
+	/*
+	 * Save xfd_err to guest_fpu before interrupt is enabled, so the
+	 * MSR value is not clobbered by the host activity before the guest
+	 * has chance to consume it.
+	 *
+	 * Do not blindly read xfd_err here, since this exception might
+	 * be caused by L1 interception on a platform which doesn't
+	 * support xfd at all.
+	 *
+	 * Do it conditionally upon guest_fpu::xfd. xfd_err matters
+	 * only when xfd contains a non-zero value.
+	 *
+	 * Queuing exception is done in vmx_handle_exit. See comment there.
+	 */
+	if (vcpu->arch.guest_fpu.fpstate->xfd)
+		rdmsrl(MSR_IA32_XFD_ERR, vcpu->arch.guest_fpu.xfd_err);
+}
+
+static inline void vmx_handle_exception_irqoff(struct kvm_vcpu *vcpu,
+					       u32 intr_info)
+{
+	/* if exit due to PF check for async PF */
+	if (is_page_fault(intr_info))
+		vcpu->arch.apf.host_apf_flags = kvm_read_and_reset_apf_flags();
+	/* if exit due to NM, handle before interrupts are enabled */
+	else if (is_nm_fault(intr_info))
+		vmx_handle_nm_fault_irqoff(vcpu);
+	/* Handle machine checks before interrupts are enabled */
+	else if (is_machine_check(intr_info))
+		kvm_machine_check();
+}
+
+static inline void vmx_handle_external_interrupt_irqoff(struct kvm_vcpu *vcpu,
+							u32 intr_info)
+{
+	unsigned int vector = intr_info & INTR_INFO_VECTOR_MASK;
+
+	if (KVM_BUG(!is_external_intr(intr_info), vcpu->kvm,
+	    "unexpected VM-Exit interrupt info: 0x%x", intr_info))
+		return;
+
+	kvm_before_interrupt(vcpu, KVM_HANDLING_IRQ);
+	if (cpu_feature_enabled(X86_FEATURE_FRED))
+		fred_entry_from_kvm(EVENT_TYPE_EXTINT, vector);
+	else
+		vmx_do_interrupt_irqoff(gate_offset((gate_desc *)vmx_host_idt_base + vector));
+	kvm_after_interrupt(vcpu);
+
+	vcpu->arch.at_instruction_boundary = true;
+}
 
 static inline bool vt_is_tdx_private_gpa(struct kvm *kvm, gpa_t gpa)
 {
@@ -111,4 +173,14 @@  static inline void __vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu,
 	kvm_vcpu_trigger_posted_interrupt(vcpu, POSTED_INTR_VECTOR);
 }
 
+static __always_inline void __vmx_handle_nmi(struct kvm_vcpu *vcpu)
+{
+	kvm_before_interrupt(vcpu, KVM_HANDLING_NMI);
+	if (cpu_feature_enabled(X86_FEATURE_FRED))
+		fred_entry_from_kvm(EVENT_TYPE_NMI, NMI_VECTOR);
+	else
+		vmx_do_nmi_irqoff();
+	kvm_after_interrupt(vcpu);
+}
+
 #endif /* __KVM_X86_VMX_COMMON_H */
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 75432e1c9f7f..d2f926d85c3e 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -527,7 +527,7 @@  static const struct kvm_vmx_segment_field {
 };
 
 
-static unsigned long host_idt_base;
+unsigned long vmx_host_idt_base;
 
 #if IS_ENABLED(CONFIG_HYPERV)
 static bool __read_mostly enlightened_vmcs = true;
@@ -4290,7 +4290,7 @@  void vmx_set_constant_host_state(struct vcpu_vmx *vmx)
 	vmcs_write16(HOST_SS_SELECTOR, __KERNEL_DS);  /* 22.2.4 */
 	vmcs_write16(HOST_TR_SELECTOR, GDT_ENTRY_TSS*8);  /* 22.2.4 */
 
-	vmcs_writel(HOST_IDTR_BASE, host_idt_base);   /* 22.2.4 */
+	vmcs_writel(HOST_IDTR_BASE, vmx_host_idt_base);   /* 22.2.4 */
 
 	vmcs_writel(HOST_RIP, (unsigned long)vmx_vmexit); /* 22.2.5 */
 
@@ -5160,7 +5160,7 @@  static int handle_exception_nmi(struct kvm_vcpu *vcpu)
 	intr_info = vmx_get_intr_info(vcpu);
 
 	/*
-	 * Machine checks are handled by handle_exception_irqoff(), or by
+	 * Machine checks are handled by vmx_handle_exception_irqoff(), or by
 	 * vmx_vcpu_run() if a #MC occurs on VM-Entry.  NMIs are handled by
 	 * vmx_vcpu_enter_exit().
 	 */
@@ -5168,7 +5168,7 @@  static int handle_exception_nmi(struct kvm_vcpu *vcpu)
 		return 1;
 
 	/*
-	 * Queue the exception here instead of in handle_nm_fault_irqoff().
+	 * Queue the exception here instead of in vmx_handle_nm_fault_irqoff().
 	 * This ensures the nested_vmx check is not skipped so vmexit can
 	 * be reflected to L1 (when it intercepts #NM) before reaching this
 	 * point.
@@ -6887,58 +6887,6 @@  void vmx_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
 void vmx_do_interrupt_irqoff(unsigned long entry);
 void vmx_do_nmi_irqoff(void);
 
-static void handle_nm_fault_irqoff(struct kvm_vcpu *vcpu)
-{
-	/*
-	 * Save xfd_err to guest_fpu before interrupt is enabled, so the
-	 * MSR value is not clobbered by the host activity before the guest
-	 * has chance to consume it.
-	 *
-	 * Do not blindly read xfd_err here, since this exception might
-	 * be caused by L1 interception on a platform which doesn't
-	 * support xfd at all.
-	 *
-	 * Do it conditionally upon guest_fpu::xfd. xfd_err matters
-	 * only when xfd contains a non-zero value.
-	 *
-	 * Queuing exception is done in vmx_handle_exit. See comment there.
-	 */
-	if (vcpu->arch.guest_fpu.fpstate->xfd)
-		rdmsrl(MSR_IA32_XFD_ERR, vcpu->arch.guest_fpu.xfd_err);
-}
-
-static void handle_exception_irqoff(struct kvm_vcpu *vcpu, u32 intr_info)
-{
-	/* if exit due to PF check for async PF */
-	if (is_page_fault(intr_info))
-		vcpu->arch.apf.host_apf_flags = kvm_read_and_reset_apf_flags();
-	/* if exit due to NM, handle before interrupts are enabled */
-	else if (is_nm_fault(intr_info))
-		handle_nm_fault_irqoff(vcpu);
-	/* Handle machine checks before interrupts are enabled */
-	else if (is_machine_check(intr_info))
-		kvm_machine_check();
-}
-
-static void handle_external_interrupt_irqoff(struct kvm_vcpu *vcpu,
-					     u32 intr_info)
-{
-	unsigned int vector = intr_info & INTR_INFO_VECTOR_MASK;
-
-	if (KVM_BUG(!is_external_intr(intr_info), vcpu->kvm,
-	    "unexpected VM-Exit interrupt info: 0x%x", intr_info))
-		return;
-
-	kvm_before_interrupt(vcpu, KVM_HANDLING_IRQ);
-	if (cpu_feature_enabled(X86_FEATURE_FRED))
-		fred_entry_from_kvm(EVENT_TYPE_EXTINT, vector);
-	else
-		vmx_do_interrupt_irqoff(gate_offset((gate_desc *)host_idt_base + vector));
-	kvm_after_interrupt(vcpu);
-
-	vcpu->arch.at_instruction_boundary = true;
-}
-
 void vmx_handle_exit_irqoff(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
@@ -6947,9 +6895,10 @@  void vmx_handle_exit_irqoff(struct kvm_vcpu *vcpu)
 		return;
 
 	if (vmx->exit_reason.basic == EXIT_REASON_EXTERNAL_INTERRUPT)
-		handle_external_interrupt_irqoff(vcpu, vmx_get_intr_info(vcpu));
+		vmx_handle_external_interrupt_irqoff(vcpu,
+						     vmx_get_intr_info(vcpu));
 	else if (vmx->exit_reason.basic == EXIT_REASON_EXCEPTION_NMI)
-		handle_exception_irqoff(vcpu, vmx_get_intr_info(vcpu));
+		vmx_handle_exception_irqoff(vcpu, vmx_get_intr_info(vcpu));
 }
 
 /*
@@ -7238,14 +7187,8 @@  static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu,
 		vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
 
 	if ((u16)vmx->exit_reason.basic == EXIT_REASON_EXCEPTION_NMI &&
-	    is_nmi(vmx_get_intr_info(vcpu))) {
-		kvm_before_interrupt(vcpu, KVM_HANDLING_NMI);
-		if (cpu_feature_enabled(X86_FEATURE_FRED))
-			fred_entry_from_kvm(EVENT_TYPE_NMI, NMI_VECTOR);
-		else
-			vmx_do_nmi_irqoff();
-		kvm_after_interrupt(vcpu);
-	}
+	    is_nmi(vmx_get_intr_info(vcpu)))
+		__vmx_handle_nmi(vcpu);
 
 out:
 	guest_state_exit_irqoff();
@@ -8309,7 +8252,7 @@  __init int vmx_hardware_setup(void)
 	int r;
 
 	store_idt(&dt);
-	host_idt_base = dt.address;
+	vmx_host_idt_base = dt.address;
 
 	vmx_setup_user_return_msrs();